1. Field of the Invention
This invention relates to lowpass harmonic filters and, in particular, to lowpass filters that are used in output circuits of communications satellites.
2. Description of the Prior Art
It is known to have lowpass harmonic filters. However, previous lowpass filters utilizing an evanescent mode technique do not have high power handling capability; they do not operate in more than one mode; they cannot be made to realize a filter response with finite transmission zeros; they are large or heavy; or, they do not operate with series capacitance in parallel to series inductance.
It is an object of the present invention to provide a waveguide lowpass filter that operates in at least two evanescent modes and can realize a filter response with finite transmission zeros.